Melatonin

Similar term(s): melatonine.

Definition:

Melatonin is a hormone formed by the pineal gland (which is located in the
center of the brain). Melatonin regulates the sleep-wake cycle and is stimulated
by darkness and inhibited by light. Melatonin is also available in some
countries as a drug or a dietary supplement which acts against insomnia and
jet-lag.